Ticks are significant vectors of disease to cattle and humans. The proposed project aims to describe the molecular interactions between the vector, Ixodes scapularis and the pathogen Borrelia burgdorferi (B. burgdorferi), the causative agent of Lyme disease. The gene expression profile of the tick salivary glands and midguts will be examined in the presence and absence of B. burgdorferi infection using a gel based differential display technique. The functions of the protein (s) encoded by the identified gene(s) will be inferred initially by computer based data mining. The functional significance of these gene products in B. burgdorferi development in the tick tissues will be explored in the presence of antibodies raised against candidate recombinant proteins. The results of this project will provide (a) an understanding of molecular mechanisms underlying the development of B. burgdorferi in the tick vector (b) provide insights into molecular manipulations of the vector in the context of B. burgdorferi infection and (c) provide clues to the function of differentially expressed spirochete and vector genes. The ultimate goal of this project is to identify novel targets based on both the vector and the pathogen for blocking transmission of Lyme disease. This investigation will also serve to pave the way for elucidation of mechanisms underlying transmission of other tick-borne pathogens.